Lv 6
goring asked in Science & MathematicsPhysics · 3 months ago

how come Photons are deemed to be mass less when the equation for its energy contains mass=E= Mass x C^2?

5 Answers

  • 3 months ago
    Favorite Answer

    Ummmmmmm ...

    Where did you get the idea that equation says something with energy must also have mass?

  • 3 months ago

    Wrong equation. E = hv where

    E= energy

    h = Planck constant, which really is "constant"

    v = frequency, NOT velocity.

    The speed of light IS NOT "CONSTANT"!!!!!

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    • Andrew Smith
      Lv 7
      3 months agoReport

      goring, your perfect square wave has an infinite acceleration unless the amplitude of your infinite frequency is zero.  So does a wave of infinite frequency with zero amplitude represent a real wave?  But what has that to do with the question?

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  • 3 months ago

    E = mc^2 only applies to an object at rest. Photons are never at rest. The full equation is 

    E^2 = (mc^2)^2 + (pc)^2

    The energy of a photon is also given by  E = hf where f is its frequency and h is planks constant. 

  • Anonymous
    3 months ago

    E= Mass x C^2 is only for stationary objects.

    In general 

    E^2 = (Mass x C^2)2 + (Momentum x C)^2

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  • 3 months ago

    They are energy, this equations tell you what their mass would be if they wre converted to mass.

    • goring
      Lv 6
      3 months agoReport

      precipitation of energy into mass cannot occur in the physical universe because  a mass in motion is said to have energy.No mass exist without motion.

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